Compensating poppet valve



April 4, 1939. R. BIRRELL 2,152,734

COMPENSATING POPPET VALVE Filed Sept. 7, 1957 l N VEN TOR. EQYDENfi/EPELL A TTORNEYS.

Patented Apr. 4, 1939 UNITED STATES PATENT OFFICE COMPENSATING POPPET VALVE Roydcn Birrell, Sacramento, Calif.

Application September 7, 1937, Serial No. 162,583

' 9 Claims. (01. 123-188) My invention relates to improvements in a compensating poppet valve, and it consists of the combinations, constructions and arrangements hereinafter described and claimed.

The standard poppet valve has a number of weaknesses due to its particular manner of mounting in an engine block. These weaknesses will be better understood when it is known that the standard poppet valve has three distinct movements while operating. The first of these movements is the opening of the poppet valve by means of a cam, the second is the moving of the valve toward closed position by a coil spring, and the third is the lateral movement of the valve head to completely seat after making initial contact with the seat during the closing movement. The third or laterally sliding movement of the valve head to completely close is caused by the spring. The spring necessarily exerts more force against one side of the valve stem than against the other due to the spring contacting with the spring seat at one point, and this will cause the valve head to first contact at one point on the valve seat during the closing movement and be fore the valve entirely seats. The part of the valve head that first contacts with the valve seat will be disposed diametrically opposite to that part of the valve stem subjected to the greatest force by the coil valve spring. The third movement of the poppet valve will therefore be a lateral sliding movement of the valve head along the valve seat as the head moves into a fully closed position. During the lateral sliding movement of the valve head in one direction. the lower end of the valve stem will be moving in the opposite direction in a pendulum-like action.

From actual experiment it has been discovered that the number of times the valve can move laterally into completely closed position is about twelve times per second, assuming that all operating conditions are perfect, such as the valve spring being at full strength and the valve guide and valve stem being polished and properly Inbricated. Under the standard operating condition for an internal combustion engine, this a would mean that the crank shaft can make 1440 Any speed above this will therefore cause the crank shaft to make approximately 3000 R. P. M. It will therefore be seen that the poppet valves are compelled to operate at a speed much greater than will permit the valves to completely perform their third operation of side slipping into the valve seat to form a complete closure. The valves will therefore be prevented from completely closing, and as soon as this occurs a number of valve weaknesses develop, caused by the valves and valve seats becoming overheated due to the blow-by of flame when the valve should be closed and prevent this. x

For example, experience under actual operating conditions has proven that valve-seat and cylinder-seat erosion occurs only at the higher speeds of an engine. This is due to the fact that the valve does not have time to completely close before it is again opened, and the flame of combustion is forced through the opening that is provided between the two surfaces and this flame impinges heavily on both surfaces causing them to burn and erode. The engineers have resorted to different metal alloys and to the cooling of the valves to cause the valves and valve seats to stand up, but the main problem of completely closing the valve after each operation, has not been solved.

The principal object of my invention is to provide a compensating poppet valve in which the head is movable laterally with respect to the valve stem in a direction that will constantly maintain it in alignment with the valve seat at all times. This is accomplished by the head repeatedly contacting the valve seat and being moved laterally by the seat so that it will continually be aligned with the seat during the entire operation of the engine. This will eliminate the third movement, i. e.. the side slippage of the valve after contacting with its seat and thus permit the valve to perfectly seat regardless of engine speed. It follows that there can be no valve weakness where there is a complete closing of the valve after each operation regardless of engine speed. This is possible only where the third movement of the valve is eliminated.

There are a number of weaknesses in the standard poppet valve which will be set forth in the body of the specification, and all of these weaknesses can be traced to the fact that the valve spring is unbalanced and therefore one side of the valve head will first make contact with the valve seat and then there will be a side slippage of the valve head while it is making its third movement in its cycle of operation to completely seat. This causes the valve to fail to close when the engine attains high. speed and the valve will overheat. About 90% of valve trouble comes from misalignment and the resulting overheating of the valve.

A number of different forms of construction may be resorted to in providing a valve head that can move laterally a slight distance in any direction with respect to the valve stem, and I have illustrated two of these forms in the accompanying drawing. It should be understood that I consider any form of valve in which the valve head proper can move laterally with respect to th lve stem, to fall within the scope of my e m ner and a coil spring I6 is disposed between invention.

Other objects and advantages will appear in the following specification, and the novel features of the device will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawing forming a part of this application, in which- Flgure 1 shows one form of the invention operatively applied to an engine block;

Figure 2 shows the valve parts being assembled; and

Figure 3 shows a modified form of' the invention.

A poppet valve must have complete longitudi nal rigidity in order that the spring will exert its full force around the entire periphery of the valve head in order to effect perfect seating. There must also be an adequate bond between the valve head and stem in order that the heat in that portion of the stem directly below the head of the valve and above the end of the valve guide (where it is at all times unprotected from the action of the exhaust flames) can travel by conduction to both the head of the valve and the lower portion of the stem, thereby keeping the temperature of this certain portion of the stem within practical limits. A valve with a head swivelled to the stem fails in these two require ments and therefore it is not practical for use a in internal combustion engines. 7

In carrying out my invention I provide a valve stem i that has a flanged head cap 2. A valve head proper 3 is placed beneath the cap 2 and is held in position by a valve head retaining member I. Figure 2 shows the flanged head cap 2 provided with a concave under-surface 5 and further shows the upper surface 6 of the retaining member as being concave. The parts are so designed that when the retaining member 4 is forced home, the surfaces 5 .and 6 are flattened out as shown in Figure 1, and will contact with the top and bottom-surfaces 1 and 8 of the valve head proper 3 for holding the valve head against accidental lateral movement with respect to the valve stem, although permitting a lateral movement as hereinafter described.

Figures 1 and 2 show. the valve head proper 3 in the form of a disc with an inclined peripheral edge 9 that constitutes a seat. The lower edge I! of the retaining member 4 is forced into a groove H in the valve stem I. Figure 2 illustrates the position of the parts before the edge I. is forced into the groove II. It is obvious that the retaining member 4 may be secured to the stem in any other desired manner.

I prefer to construct the parts so that a force of approximately two hundred pounds .is neces- -sary to move the valve head proper 3 laterally with respect to the valve stem I. The amount of force depends upon the strength of the valve spring with the valve closed. If the spring presturn is carried by an engine block indicated generally at II. The usual clearance betweenthe valve stem and the valve stem guide is from .015" to .008". A valve spring seat I5 is carried by the lower end of the valve stem in the usual manthe valve seat and a flange I! that is integral with the valve guide l3. A valve lifter indicated generally at I8 is disposed beneath the valve stem and the usual clearance between the valve lifter and the valve stem is from .004" to .018", when the parts are in heated condition from operating.

Figure 1 shows the valve head 3 resting on a. valve seat l9 formed in the engine block II. The valve head proper 3 closes the seat l9 which may be provided for either an intake port or an exhaust port 20. The engine block is provided with the usual space 2| for water.

Before describing the operation of this form of the invention, it is best to set forth the modifled form because both forms operate in the same manner. In Figure 3, I show a valve stem 25 provided with a flanged head 26 and this head receives a valve head proper 21 that is in the shape of a disc and has a central opening 23 for loosely receiving the stem. A retaining member 29 is mounted on the stem and is disposed beneath the valve head proper so as to force the head into frictional contact with the undersurface of the flanged head 20. The lower end 30 of the retaining member may be rolled into a groove 3| formed in the valve stem 25. The retaining members may be secured to the valve stem in any other manner desired such as by welding.

A cap 32 is placed over the flanged head 26 and has a central projection 33 that'contacts with the center of the flanged head. The periphery of the cap is flanged and then is roll-riveted to the periphery of the valve head proper. The valve head has a recess 34 for receiving the flange 35 of the cap. It is possible to secure the flanged portion of the cap to the valve head proper by any other means such as by a torch or by electric welding.

It will be seen from either form of the inven-. tion that the valve head proper 3 or 21 may move laterally in any direction with respect to the valve stem l or 25 and thus provide a perfect se'at between the valve head 3 or 21 and the seat I 9. The valve shown in Figure 3 is operatively mounted in an engine block in the same manner as that illustrated in Figure 1.

From the foregoing description of the various parts of the device, the operation thereof may poppet valve to its normal. position causes this valve to' contact with the valve seat It at one point because the coil spring will exert its greatest force at one point on the spring seat ii. If.

for example, the spring i8 contacts with the spring seat at the point marked X, then the lower end of the valve stem will be swung to the left in Figure 1 so that the stem will contact with the lower end of the valve guide at the point Y. This will cause the upper portion of the valve stem to contact with the top of the valve guide at Z. The result of this is that the valve head in the standard poppet valve will first contact valve seat [9 at C. Further movement of the spring seat in a downward direction by the spring iii will cause the valve head to slide laterally to the left in Figure l and the lower end of the valve stem will swing to the right, until the valve becomes perfectly seated or fully closed.

With my form of invention the valve head proper 3 or 21, in contacting with the seat l9 at C, will move the valve head proper laterally a distance that is sufiicient for the valve head to properly seat thereafter without side slippage, eventhough the coil spring continues to exert a greater force at the point X than at any other point on the valve seat IS. The result is that the lateral sliding movement of the valve head in a standard poppet valve at the end of each cycle of movement, is entirely eliminated and the valve will therefore have only two operations, an opening operation, caused by the valve lifter, and a closing operation, caused by the valve spring.

As already stated, it is necessary that a poppet valve have what is termed longitudinal rigidity as well as a suflicient bond between the head and valve stem. Longitudinal rigidity permits the contacting surfaces between the valve and the valve seat to contact with the full pressure of the spring, whatever that pressure may be. The present invention still permits this longitudinal rigidity, even though the valve head proper may shift laterally with respect to the head. The present invention also provides suflicient bond between the head and the stem because of the great area between the contacting surfaces of the valve head proper and the parts that connect the head to the valve stem. It will therefore be seen that the present invention has every advantage possessed by the standard poppet valve and has the added advantage of never getting out of alignment.

While I have shown only the preferred forms of my invention, it should be understood that various changes or modifications may be made within the scope of-the appended claims without departing from the spirit of the invention.

I claim:

1. A poppet valve having a head movable laterally with respect to the valve stem in any direction and means carried by the stem for maintaining the axis of the head parallel with the stem axis at all times and for preventing the head from swinging into an angular position with respect to the stem.

2. A poppet valve comprising a stem, a discshaped head movable laterally with respect to the stem, and means carried by the stem and en-- gaging with the top and bottom of the head for holding the plane of the head at right angles with the axis of the stem at all times.

3. A poppet valve having a stem with a flanged end, a valve head provided with an opening large enough to loosely receive the stem, a retaining member for holding the head against the flanged end, and a cap secured to the valve and covering the flanged end, said cap bearing against the flanged end.

4. A poppet valve having a stem with a flanged end, a valve seat-engaging portion slidably contacting with the flanged end and having an opening larger in diameter than the stem, and a retaining member mounted on the stem and cooperating with the flanged end for frictionally engaging with the valve seat-engaging portion for .holding the portion against lateral movement until a predetermined force is exerted in a direction to move the head laterally, said flanged end and retaining member holding the portion against any swiveling action during such movement.

5. A poppet valve having a stem with a flanged head extending at right angles to the stem, a retaining member extending at right angles to the stem, a valve head slidably mounted between the flanged head and the retaining member and being movable in a radial direction with respect to the stem, said flanged head and retaining member keeping the axis of the valve head parallel with the stem axis at all times.

6. A poppet valve comprising a stem having a flanged head extending at right angles thereto, a retaining member extending at right angles to the stem, the opposing faces of the flanged head and retaining member being slightly concave, and a valve head having a thickness slightly greater than the least distance between the opposing faces, whereby the opposing faces will frictionally grip the valve with sufficient force to necessitate a predetermined lateral force being applied to the valve head in order to move it laterally with respect to the stem.

7. A poppet valve comprising a stem with flanged head and a retaining member spaced from the head, a valve head slidable between the flanged head and the retaining member, and a cap carried by the valve head and covering the flanged head.

8. The combination with a poppet valve seat having an inclined conical-shaped wall, of a poppet valve having a stem with a flanged end, a valve seat-engaging portion slidably contacting with the flanged end, and having an opening larger in diameter than the stem, and a retaining member mounted on the stem and cooperating with the flanged end for frictionally engaging with the valve seat-engaging portion for holding the portion against lateral movement until a predetermined force is exerted by the valve seat upon a successive series of the seating of the valve, for moving the head laterally, said flanged end and retaining member holding the portion against any swivelling action during such movement, and holding the portion against lateral movement when striking a foreign particle that adheres to the portion or to the seat.

9. A poppet valve comprising a stem having a flanged head and a groove spaced from the head, a disc-shaped valve seat-engaging portion having an opening for receiving the stem and permitting lateral movement in any direction, a retaining member having an end suitable for crimping and engaging with the walls of the groove, said member frictionally engaging with the portion, and frictionally holding it against the flanged head for holding the portion against rockingor swiveling movement when the portion is moved laterally.

ROYDEN BIRREIL. 

